But people who know and use the words foo and bar are almost exclusively developers, so they should know better eveb when typing a fake address to a random form. But it’s easy to type reflexively, without thinking, so I’m not surprised people do it.

I'll be honest, even I do this when it's a form that has an email requirement but that I don't otherwise care about at all. I'm not gonna sign myself up for spam. Sometimes example.com and whatever other testing TLD that comes to mind is blocked because they want something that could plausibly be a real email address, so I give them something that could plausibly be a real email address, like [email protected]

That's why I own fakefakefake.email it gives me some minor pleasure to provide this email address to people who insist on having an email address for me.

I use @mailinator.com for that purpose, it's oddly satisfying to put "[email protected]" / etc in those places.

A lot of forms reject @mailinator.com and similar domains.

Then you use one of their alternate domains. Or you point a domain to one of their alternates.

Check out the MX record for meowcats.fun, for example. It points to suremail.info, which points to mailinator. I have never had that domain rejected by a form.

Shhh, don't tell anyone ;)

I've been using [email protected] just because it's quick & easy to type. I just looked it up, and it seems all the single-letter .com domains are reserved, so it should be fine.

Isn't x.com owned by paypal?

The fact that it is a valid address is a feature, as some sites that demand email addresses (so they can spam you) verify the address for correctness. People are intentionally choosing an address that appears valid, because it is valid. So, sorry to the guy who bought bar.com, but that's what he signed up for.

Correctness and existence are two different things. I doubt many sites explicitly exclude @example.com or @*.test in their email validator.

I usually use [email protected] and the like...

I would steer well clear of .gov and .mil when providing fake anything.

Impersonating federal agents is shockingly illegal and the authorities who enforce this have absolutely no sense of humor.

The risk is low but why take it?

That risks getting you in trouble with Secret Service.

I usually use postmaster@theirdomain so they can spam themselves to an address they (in theory) cannot just ignore mail to.

Actually, for a while I used example.com a lot and I was surprised how often it worked just fine.